The present invention relates to control systems for ice dispensers and icemakers, and in particular to an improved control system which agitates and levels ice in a hopper of an ice dispenser in a manner to maintain an icemaker continuously operative whenever the hopper is less than full.
In the food and beverage service industries, it is desirable to provide means for expeditiously dispensing a quantity of ice, for example into a glass, to facilitate service of ice water and cold beverages to customers. Conventionally, the means comprises an ice dispenser, which for commerical application usually includes a hopper for storing a mass of discrete particles of ice, an icemaker for manufacturing ice for the hopper, a thermostat in the hopper for sensing the level of ice and controlling operation of the icemaker, and an agitator for leveling and preventing congealing or agglomeration of the mass of ice in order to maintain the ice particles in discrete, free flowing form. An opening at the bottom of the hopper enables ice to be removed from the hopper, for example by a dispensing unit which automatically dispenses ice.
The thermostat is positioned generally at and beneath the point of entrance of ice into the hopper to prevent overfilling. Ice therefore tends to build up around the thermostat, and may trip the thermostat when the hopper is only partially full. In conventional control schemes, contact of ice with the thermostat stops the icemaker and operates the agitator to level the mass of ice. If ice drops away from the thermostat upon agitation, the icemaker is restarted and the cycle repeated. Ordinarily, in bringing the hopper to a completely full condition, the agitator and icemaker are cycled several times before the level of ice is high enough to remain about the thermostat, whereafter the icemaker remains off until sufficient ice has been dispensed to again drop its level to below the thermostat. A disadvantage to the technique is that the icemaker is cycled through a large number of on-off cycles in maintaining the hopper full, so the compressor and other components of the refrigeration system are subject to increased wear and a decreased operating life and reliability.
In improving upon prior control systems for icemakers and ice dispensers, according to U.S. Pat. No. 4,227,377 to Benjamin D. Miller, assigned to the assignee of the present invention, a control system maintains an icemaker continuously operative whenever a hopper of an ice dispenser is less than completely full. This is accomplished by continuing to operate the icemaker while simultaneously agitating and leveling the ice in the hopper whenever ice builds up around a thermostat in the hopper, and thereafter sensing whether the ice has dropped away from the thermostat. If it has, the icemaker is maintained in operation and the cycle is repeated. If it has not, the icemaker is turned off until sufficient ice is dispensed from the hopper to again drop its level to below the thermostat. In this manner, the number of on-off cycles of the icemaker are minimized in maintaining the hopper completely full. However, although the scheme works well with icemakers that introduce ice relatively slowly into the hopper during an ice harvest cycle, if used with an icemaker that introduces a large quantity of ice relatively quickly into the hopper, during harvesting ice in the hopper may rapidly build up and block the ice discharge chute from the icemaker, before the thermostat senses the ice and causes agitation and leveling, and/or "fool" the thermostat into thinking that the hopper is completely full, when in fact it is not.